Fuel control and ignition system



Nov. 1, 1960 Filed July 16, 1958 G. F. LAING FUEL CONTROL AND IGNITION SYSTEM 6 Sheets-Sheet 1 INVENTOR. Gordon f? Zaz'fl BY J Filed July 16, 1956 Nov. 1, 1960 G. F. LAING 2,958,377

FUEL CONTROL AND IGNITION SYSTEM 6 Sheets-Sheet 2 INVENTOR.

Gordon 1? 10.2739

Nov. 1, 1960 Filed July 16, 1956 G. F. LAlNG FUEL CONTROL AND IGNITION SYSTEM 6 Sheets-Sheet 3 INVENTOR Gordon J? Zain Nov. 1, 1960 G. F. LAlNG 2,958,377

FUEL CONTROL AND IGNITION SYSTEM Filed July 16, 1956 6 Sheets-Sheet 4 IN VEN TOR. Gordon F Z z in 9 Nov. 1, 1960 G. F. LAING 2,958,377

FUEL CONTROL AND IGNITION SYSTEM Filed July 16. 1956 N 6 Sheets-Sheet 5 0 EM P N I. K k 2} X7 3 g INVENTOR. (iariaiaj? 1 WQMZZZZZZ;

Nov. 1, 1960 G. F. LAING 2,958,377

FUEL CONTROL AND IGNITION SYSTEM Filed July 16, 1956 6 Sheets-Sheet 6 INVENTOR. GORDON E LAING ATTORNEY Patented Nov. 1, 1950 FUEL CONTROL AND IGNITION SYSTEM Gordon F. Laing, Delavan, Wis, assignor to Base Inc, a corporation of Wisconsin Filed .Iuly 16, 1956, Ser. No. 598,653

25 Claims. (Cl. 158--128) This invention relates to improvements in fuel control and ignition systems for fluid fuel burning apparatus.

It is a general object of the present invention to provide an improved fuel control and ignition apparatus for fluid fuel burning equipment having main and pilot burners and having electric ignition means for said pilot burner, said apparatus having main and pilot burner fuel control valves and a switch for controlling said ignition means, there being an electroresponsive prime mover for actuation of said valves and switch in a predetermined sequence to effect fuel flow to said pilot burner and ignition of the fuel thereat, followed by delivery of fuel to the main burner and ignition of said fuel by the flame of the burning fuel at the pilot burner.

A further object of the invention is to provide an improved control device in which there is a prime mover, a control member and a releasable force transmitting connection between said prime mover and control member including first and second releasable latching means each responsive to a difierent condition, said force transmitting connection being operative to transmit force effective to actuate said control member only when both of said conditions are satisfied and said latching means are latched.

Another object of the invention is to provide an improved fuel control and ignition apparatus having means therein for preventing opening of the main fuel valve by the operation of the prime mover until after the fuel has been successfully ignited at the pilot burner, said means also effecting closure of the main fuel valve in the event of outage of the flame at the pilot burner while said main fuel valve is being held open by the prime mover.

Still another object of the invention is to provide an improved fuel control and ignition apparatus of the character described wherein there is cycling actuating means driven by the prime mover and resettable shut-off means actuated to a shut off position eifecting deenergization of said prime mover and shut off of the fuel flow to said pilot burner in the event of failure of the ignition means to ignite the fuel at the pilot burner after a predetermined number of cycles of said cycling actuating means.

Another object of the invention is to provide an improved fuel control and ignition system of the aforementioned character which is so constructed that failure of the electric power to the prime mover at any time cannot result in any fuel valves being held open.

A more specific object of the invention is to provide an improved fuel control and ignition system of the class described wherein the prime mover is uni-directional and there is means for stalling the energized prime mover when the main fuel valve is moved thereby to open position, there being temperature responsive means for energizing and deenergizing said prime mover in response to predetermined changes in temperature, and a releasable force transmitting connection between said prime mover and said main fuel valve including a rotatable actuating member operable in one direction by operation of said prime mover to a stalled open valve position and in the reverse direction to a retracted position permitting closure of said main fuel valve on deenergization of said prime mover, said cycling of said main valve being accomplished without actuation of said ignition means as long as the pilot burner remains ignited, so that the ignition means is not unnecessarily energized, and its longevity is thereby increased.

Another object of the invention is to provide an improved fuel control and ignition system in one embodiment of which all fuel flow to both the main and pilot burners is terminated in response to predetermined temperature changes, and in another embodiment of which the main burner can be cycled in response to predetermined changes in temperature while continuous fuel flow to the pilot burner is permitted as long as a flame exists at said pilot burner.

Another specific object of the invention is to provide an improved fuel control and ignition system of the aforementioned character wherein the releasable force transmitting connection between the prime mover and the main fuel valve is under the control of electromagnetic holding means energized by a thermoelectric generator subject to the heat of burning fuel at the pilot burner, there being means for positively releasing said holding means in response to deenergization and reenergization of said prime mover, even though said holding means may be energized by the thermoelectric generator at the time of said release, thus requiring the improved apparatus to complete an ignition cycle for ignition of the fuel at the pilot burner before the main fuel valve can again be reopened in response to the thermostat calling for heat, and thereby preventing opening of the main fuel valve on said reenergization of the prime mover after extinguishment of the flame at the pilot burner and before cooling of the generator sufficient to effect release of said holding means.

Other and further objects of the invention will become apparent as the description proceeds, reference being had to the accompanying drawings illustrating two forms of the invention wherein:

Figure 1 is a plan view of the improved fuel control and ignition apparatus with the cover, together with the prime mover, its mounting plate and driving gear, removed;

Figure 2 is a sectional plan view similar to Figure 1 and taken approximately along the lines 2-2 of Figure 3;

Figure 3 is a vertical sectional view of the improved fuel control and ignition apparatus taken approximately along the line 3-3 of Figure l and showing the parts removed in Figure 1;

Figure 4 is a sectional plan view taken approximately along the line 4-4 of Figure 3;

Figure 5 is an enlarged fragmentary vertical sectional view taken approximately along the line 5-5 of Figure 2;

Figure 6 is a semi-diagrammatic view showing the wiring diagram of the improved fuel control and ignition apparatus connected for the control of a unit heater type of fuel burning equipment of the sealed combustion chamber type, the latter being shown in vertical section;

Figure 7 is a fragmentary plan view of a portion of another form of the improved fuel control and ignition apparatus, illustrating means for holding the pilot burner fuel valve open during cycling of the main burner fuel valve; and

Figure 8 is a fragmentary exploded perspective view showing the positional relationship of the various working parts of the device shown in Figures 1 to 7.

While the improved fuel control and ignition apparatus is shown and described in connection with a specific gaseous fuel burning unit heater of the type having a sealed combustion chamber, it is to be understood that the improved apparatus is not limited to use with this type of equipment, but is adapted for use equally well with other gaseous fuel burning equipment, for example clothes driers, water heaters, commercial and central house heating equipment and other types of space heaters.

Referring now to Figure 6, the fluid fuel burning equipment selected for illustration therein with the improved fuel control and ignition apparatus takes the form of a unit heater 11) having a generally cylindrical casing 11 provided with a cool fresh air inlet throat 12 centrally of the bottom wall thereof and having suitable peripheral warm air outlet means 13 which may take the form of one or more louvered openings for deflecting the warm air downwardly. Disposed coaxially within the casing 11 is a combustion chamber-heat exchanged unit 14 comprising hollow annular chamber members 15, 16 and 17. The chamber 15 has a greater axial dimension than do the chambers 16 and 17, and is supplied with fresh air for combustion through a fresh air inlet conduit 18. Diametrically opposite the fresh air inlet conduit 18, the chambers 15 and 16 are interconnected by a circuit 19, and adjacent the fresh air inlet conduit 18, the chambers 16 and 17 are connected by a conduit 20.

Disposed coaxially within and spaced from the cornbustion chamber-heat exchanger unit 14 is an electric motor 21, the shaft 21a of which projects from both the upper and lower ends thereof. The lower end of the motor shaft 21a carries a fan 22 disposed within the air inlet throat 12, and the upper end of said shaft is connected to drive the impeller of a centrifugal blower 23. A conduit 24 connects the inlet of the blower 23 with the chamber member 17 at a point diametrically opposite the connection of said chamber With the conduit 20. The outlet of the blower 23 is connected with an exhaust conduit 25 and, as shown in Figure 6, the fresh air inlet con duit 18 may be enlarged to concentrically surround the exhaust conduit 25 to provide for the transfer of heat from the hot exhaust gases to the incoming fresh air.

It will be observed that operation of a motor 21 and thereby rotation of the fan 22 causes fresh air to be drawn into the throat 12 around and between the chamber elements 15, 16 and 17 for transfer of heat to said air and discharge of the heated air through the outlet means 13. At the same time, operation of the motor 21 and thereby of the centrifugal blower 23 is operable to exhaust hot gases of combustion from the combustion chamber-heat exchanger unit 14 through the conduit24, blower 23 and conduit 25, and at the same time to draw fresh air into said unit through the inlet conduit 18. Since the conduits 18 and 25 extend externally of the space being heated, the unit heater does not utilize for combustion any of the air within said space, and the chamber 14, thus being sealed from the space being heated, may be operated at a pressure somewhat blow atmospheric pressure if desired.

Disposd within the chamber portion of the unit 14 is-a main burner 26 which may be supplied with gaseous fuel through a fuel supply conduit 27. A pilot or ignition burner 28 is disposed in operative reiation adjacent the main burner 26 and is adapted to be supplied with fuel through a conduit 29.. A flame sensitive device, which may take the form of a thermoelectric generator or thermocouple 30, is mounted within the chamber member 15 and has hot junction means subject to the heatof the flame of burning fuel at the pilot burner 28. Also mounted adjacent the pilot burner 23- is an electric igniter element 31 which is operable when energized to ignite gaseous fuel emitted from the pilot burner 28. 7

Referring now to Figure 3 of the drawing, the improved fuel control and ignition apparatus comprises a base casting 32 to one side of which a valve body casting 33 is sealingly attached, as by screws 33' and a gasket 35. A rectangular cup-shaped cover 36 is removably secured to the base casting 32 and encloses the operating mechanism carried thereby.

As shown most clearly in Figure 4, the valve body casting 33 is formed with a chamber 34 and is provided with a fuel inlet port 35 which may be connected to a suitable source of gaseous fuel under pressure by a supply conduit 36. The valve body member 33 is also formed with a fuel outlet port 37 provided at its inner end with an annular valve seat 38 and adapted to threadedly receive at its outer end the fuel supply conduit 27 which extends to the main burner 26. The valve body member 33 is formed with a cylindrical chamber 39 for receiving a filter 40, there being a pilot fuel passage 41 affording communication between the chamber 34 and the chamber 39, fuel flow into said passage being controlled by a pilot fuel valve 4-2 movable to flow-permitting and flowpreventing relation with respect to the passage 41. The valve 42 is pivotally connected to a pivotally mounted bell crank lever 4-3, and a spring 44 is connected to said lever to bias the latter in a clockwise direction as viewed in Figure 4, and to thereby bias the pilot valve member 42 toward flow-preventing position. A pilot fuel passage 45 affords as outlet from the filter chamber 33 and at its outer end receives the pilot fuel supply conduit 29 which extends to the pilot burner 28. A metering valve 46 may be interposed in the passage 45 as shown to control the amount of fuel which can flow to the pilot burner through the passage '45. The afore-described arrangement is such that all fuel flowing to the pilot burner must flow through the filter 40.

Referring now to Figures 1 and 2, the base casting 32 is formed with upstanding angular lugs 47, 48 and 49 and with an upstanding post 50. A motor mounting and bearing plate 51 is supported on and secured to the upper ends of angled lugs 47 and 4 8 and post 59, the shape of said plate being shown in dot and dash lines in Figure 1, and securement of said plate being effected by screws 52, 53 and 54 shown in cross-section in Figure 1.

As shown in Figure 3, an electroresponsive prime mover 55, which may take the form of an electric motor having a built in speed reduction gear unit, is fixedly supported on the plate 51 and has a depending drive shaft 56 extending through a suitable aperture 57 in the plate 51. A driving gear 58 is fixed, as by a set screw, to the lower end of the drive shaft 56, said gear, in the illustrated embodiment, being a bevel type gear.

A main valve shaft 59 is journaled at its upper end in a suitable aperture 62 in the plate 51 and rotatably extends through a bored boss 60 depending from the under side of the base casting 32, there being a suitable gas seal 61, for example a resilient O-ring, surrounding said shaft within the boss 6!). Fixed to the lower end of the shaft 59 within the chamber 34 is a main valve arm 63 which carries a main fuel valve 64 cooperable with the annular seat 38 to control the flow of gaseous fuel to the main burner 26. Fixed to the upper end of the shaft 59 adjacent plate 51 is an arm 65 (Figure 1) having its outer end apertured to afford a connection with a tension spring 66 which is anchored at its opposite end to the angular upstanding lug 48 which is apertured to receive the same as shown in Figure 3. The spring 66 biases the arm 65, shaft 59, and the valve arm 63 in a counterclockwise direction as viewed in Figures 1 and 2, thereby biasing the main fuel valve 64 toward closed or flow-preventing position with respect to the seat 38.

A main fuel valve actuating linkage operable to permit actuation of the main fuel valve to open position by the prime mover 55 when a flame is present at the pilot burner 28 and to prevent disposition of the main fuel valve in open position whensuch a flame is absent, comprises a pivotal lever 67 formed with a vertically extending cross arm portion 67a terminating in outturned lugs 68 adjacenttthe base casting 32 and plate 51 respectively. The lugs 68 are apertured to receive a shaft 69, thelatter being journaled at its upper end in a suitable aperture (not shown) in the plate 51 and at its lower end in a suitable aperture (not shown) in the base casting 32. One end of the lever 67 is pivotally connected, as by a pin 70 with a link 71, the latter being similarly connected, as by a pin 72, to a link 73 which, in turn, is pivotally connected to an intermediate portion of the arm 65, as by a pin 74. The link 73 is formed with a downturned lug 75 for a purpose to be hereinafter described.

The opposite end of the lever 67 is pivotally connected to the reciprocatable stem 76 of a releasable holding or latching means indicated generally by the numeral 77. The latching means 77 comprises a cylindrical hood or a casing 78 which is fixedly mounted on the upstanding lug 49, and fixedly disposed Within the casing 78 is an electromagnet 79 comprising a U-shaped frame 80 and an energizing winding 81. An armature 82 is connected for movement with the shaft or stem 76 between the attracted position shown and a retracted position out of engagement with the pole faces of the magnet frame 80 toward which position said armature and stem are biased by a helical compression spring 83. As shown, the spring 83 surrounds the stem 76 and is interposed between the adjacent end wall of the casing 78 and shoulder means 84 carried by the stem 76. The electromagnet 79, when energized, is adapted to hold the armature 82 in said attracted position when moved thereto against the bias of the spring 83.

Referring to Figures 1 and 3, a shaft 85 coaxial with the drive shaft 56 is journaled at its lower end in a bearing bore 86 formed in the base casting 32. Fixed on the upper end of the shaft 85 adjacent the drive gear 58 is an annular hub 87 formed with a radially extending arm 88 which carries at its outer end an actuating roller 89 disposed below the plane of the links 71 and 73 and in the plane of the lever 67 and downturned lug '75 of the link 73. Intermediate its length the arm 88 extends through and rotatably supports a planet pinion 90 which is of the bevel type and meshes with the drive gear 58. Mounted on the shaft 85 adjacent the hub 87 and free to rotate with respect to said shaft is a bevel gear 91 which meshes with the planet pinion 90. The gears 58 and 91 and pinion 90 form a differential gear set. The shaft 85 is splined, as at 95 (Figure 3), adjacent the base casting 32, and above said splined portion a cam member 96 is fixed on said shaft, said cam being positioned for coaction with a pair of normally open ignition contacts 97 suitably mounted on the base casting 32 as shown.

Fixed to the under side of the bevel gear 91 is an actuating and locking member 92 which may take the form of an annular plate having a first pair of diametrically oppositely disposed depending peripheral actuating lugs 93 (Figures 2 and 5). The member 92 is also formed with a pair of diametrically oppositely disposed depending peripheral locking lugs 94 which are shorter in length than the lugs 93 and are angularly offset therefrom as Well as being disposed radially outwardly from the shaft 85 a distance greater than the lugs 93.

The base casting 32 is formed with a bored boss 98 (Figure 5) depending into the chamber 34, and a shaft 100 rotatably extends through said bored boss and may be provided therein with gas sealing means, for example an O-ring 99. Within the chamber 34 an arm 101 (Figure 4) is fixed to the lower end of the shaft 100 and is adapted to be engaged by the bell crank lever 43. An arm or bar 102 is fixed at one end to the upper end of the shaft 100 and, as shown most clearly in Figure 5, fixedly carries adjacent its opposite end an upstanding shaft 103. A sleeve or hub 104 is rotatable on the shaft 103 and has fixed thereto a spur gear 105 of substantially larger diameter. The gear 105 carries an upstanding pin 106 for a purpose to be hereinafter more fully described, and a helical torsion spring 107 surrounds the hub 104 and has one end anchored to the pin 106 and its opposite end anchored in a suitable aperture in a. plate 108 fixed to the shaft 103. The spur gear 105 also carries a depending pin 109 which is engageable with the far edge of the bar 102 as viewed in Figure 5, to limit the clockwise rotation of the gear 105 as viewed in Figures 1 and 2. The torsion spring 107 biases the gear 105 in said clockwise direction and the pin 109 into engagement with the arm 102. The spur gear 105 is engageable with the splined portion of the shaft 85, and the pilot valve biasing spring 44 (Figure 4), acting through the bell crank lever 43, the arm 101, shaft 100, and the arm 102, biases the spur gear toward a position out of engagement with the splined portion 95 of the shaft 85, said gear being disengaged from said splined portion when the pilot valve 42 is in flow-preventing position. Movement of the spur gear 105 into engagement with the splined portion of the shaft 85, of course, acting through the aforedescribed linkage, effects opening of the pilot valve 42 against the bias of the spring 44.

Means is provided for releasably locking the lower gear 91 to effect, by rotation of the drive gear 58, planetary movement of the planet pinion 90 and thereby corresponding movement of the actuating roller 89 for performance of actuating functions hereinafter more fully described. The aforementioned locking means comprises a locking lever 110 (Figures 3 and 5) which is generally T-shaped in side elevation and the cross bar of which terminates in spaced parallel apertured lugs 111. A pivot shaft 112 has its lower end journaled in a suitable bearing aperture in the base casting 32, and has its upper end journaled in a suitable aperture in the plate 51, said shaft extending through the apertured lugs 111 and providing a pivotal support for the locking arm 110.

The end of the locking arm 110 opposite the lugs 111 is connected to the stem 113 of a latching or holding means 114, the latter being similar to the holding or latching means 77 and being fixedly mounted on the upstanding angled lug 48 as shown in Figure 2. The latching means 114 comprises an electromagnet 115 having a U-shaped frame 116 and an energizing winding 117,. there being an armature 118 biased toward a retracted position with respect to the pole faces of the magnet frame 116 by a biasing spring 119. When the winding 117 is energized, the electromagnet 115 is operable to hold the armature 118 in attracted position when moved thereto against the bias of the spring 119.

In Figure 5 it will be noted that the locking lever 110 has an upper edge portion 120 spaced slightly below the plane of the lower end of the locking lugs 94 and above the plane of the lower ends of the actuating lugs 93. It will also be observed that the lever 110 has an upstanding locking lug 21 positioned in the plane of the locking lugs 94, and that said lever has a cut away upper edge portion 122 spaced slightly below the plane of the lower ends of actuating lugs 93. Thus, upon counterclockwise rotation of the member 92 with lower gear 91, the actuating lugs 93 are engageable with the inner surface of the upper edge portion 120 of the locking lever 110 to pivot the latter in a clockwise direction as viewed in Figures 1 and 2 and thereby move the armature 118 into engagement with the pole faces of the electromagnet 115 against the bias of the spring 119. If the armature 118 is held in attracted positon by energization of the electromagnet 115, the locking lug 94 adjacent the actuating lug 93 effecting such resetting is engageable, upon further movement of the resetting lug 93 beyond the upstanding locking lug 121 and out of engagement with the lever 110, with said upstanding locking lug to prevent further counterclockwise rotation of the member 92 and gear 91.

Means is also provided for actuating the spur gear 105 into meshing engagement with the splined portion 95 of the shaft 85 to thereby effect opening of the pilot valve 42 in response to successful resetting of the armature 118, said means comprising a lever 123 which is also generally T-shap'ed in side elevation, as shown most clearly in Fig. 5. As shown in Figures 1 and 2, the lever 123 is of irregular configuration in plan view, the cross bar portion thereof being turned at an angle and provided at the upper and lower ends thereof with apertured spaced parallel lugs 124. A pivot shaft 125 is journaled at its opposite ends in suitable apertures in the base casting 32 and the plate 51 respectively, and is received in the apertured lugs 124 to provide a pivotal mounting for the lever 123. The opposite end of the lever 123 terminates in an arcuate portion 126 (Figures 2 and 5) and has an upper edge portion 127 (Figure 5) extending. inwardly from the terminus thereof and terminating in outturned shoulder or flange member 128. The upper edge portion 127 is in a plane which is above the plane of the lower ends of the actuating lugs 93, and. is therefore engageable by said lugs. The lever 123 is also formed with a cut away upper edge portion 129 which is in a plane spaced below the plane of the lower ends of the actuating lugs 93, and hence is not engageable by said lugs. The upper edge portion 127 is also spaced below the plane of the lower ends of the locking lugs 94 and therefore the lever 123 is not engageable by said lockinglugs.

The arcuate portion 126 of the lever 123 carries an angled member 130 which projects outwardly and downwardly from the lower edge of said portion and is engageable with the upper end of the shaft 103. A tension spring 131 is connected at one end to the locking lever 110 and at its opposite end to the lever 123 as shown most clearly in Figures 1 and 2, and when the armature 118 of the latching means 114 is in released position, said spring exerts no substantial biasing force on either of the levers 110 and 123. When, however, the armature 118 is moved toward the attracted position shown, the pivotal movement of the locking lever 110 producing such armature movement pulls on the end of the spring 131 connected thereto, and through said spring exerts a bias on the lever 123 tending to pivot the latter in a clockwise direction as viewed in Figures 1 and 2. When the lever 123 is pivoted in a clockwise direction, the engagement of the depending lug 130 with the upper end of the shaft 103 moves the spur gear 105 into meshing engagement with the splined portion 95 of the shaft 85, and at the same time causes pivotal movement of the arm 102, shaft 100, arm 101, and bell crank lever 43, to open the pilot valve member 42 against the biasof the spring 44.

The pilot valve 42 does not, however, move to open position simultaneously with resetting of the armature 118' to attracted position. Instead, as one of the actuating lugs 93 moves ina counterclockwise direction to actuate the locking lever 110and' resetthearmature 118 against the bias of the spring.119,.the opposite actuating lug 93 engages the inner surface of the upper edge portion 127 of the lever 123 to hold said lever against the bias exerted by the spring 131 during said resetting, so that the downturned lug 130 cannot pull the shaft 103 toward the shaft 85 for opening movement of the pilot valve 42 during the resetting operation. It is not until after the resetting actuating lug 93 has moved beyond the upstanding lug 121 of the lever 110 to a position permitting inward movement of the lever 110 under the bias: of the springs 119 and 131 in the event of failure of the armature 118 to be held in attracted position when reset thereto, that the opposite actuating lug 93 moves beyond the outturned lug 128 and out of engagement with the upper edge portion 127 of the lever 123 to permit inward movement of said lever under the bias of the spring 131 and opening of the pilot valve 42. As the lever 123 moves inwardly, the aforementioned opposite actuating lug 93 remains engageable with the outturned lug 128 to lock the lower gear 91 against any substantial clockwise rotation, while the latter is locked against any substantial counterclockwise rotation by co action of the lugs 121 and 94;

If the armature 118' should fail to be held in attracted position by'theelectrornagnet 115, the resultant inward movement of the locking lever under the bias of the spring 119 not only removes the pulling stress said lever exerted on the spring 131, to thereby prevent opening of the pilot valve 42 thereby,- but it also moves the upstanding locking lug 121 radially inwardly of the path of the depending locking lugs 94 to prevent locking coaction of said lugs and free the lower gear 91 for rotation.

The base casting 32 is also formed with a pair of upstanding lugs 132 and 133 (Figures 1 to 3) having aligned bearing apertures 134 and 135 (Figure 3) respectively. The upstanding angled lug 47 is also formed with a bearing aperture 136 which is also coaXially aligned with the bearing apertures 134 and 135. Axially slida-bly positioned in the bearing apertures 134, 136' and 135 is a cylindrical plunger 137 which carries a washer 138 engageable wtih the lug 132 to limit the inward movement thereof. Intermediate the lugs 47 and 133 the plunger 137 is formed with a reduced diameter portion 139 having at the outer end thereof a frusto-conical surface portion 140. Suitably mounted on the base casting 32 adjacent the plunger 137 are pair of normally open contacts 141 and 142. When the plunger 137 is moved outwardly from the position shown in Figure 3 to the point where the reduced diameter portion 139 of said plunger is positioned below the contact 142, said contact is positioned out of engagement with the contact 141. Movement of the plunger 137 inwardly to the position shown, however, causes the surface portion 140 of the plunger to engage the contact 142 and move the latter upwardly into engagement with the contact 141, the contact 142 being held in said position by movement of the larger diameter portion of the plunger underneath said contact as shown in Figure 3. The plunger 137 and the contacts 141 and 142 remain in the position shown indefinitely once the plunger 137 is reset to said posi tion. The inner end of the plunger 137 is formed with a conical tip 143 which, when the plunger 137 is in the position shown, is in the path of movement of the pin 106 carried by the spur gear 105 as shown in Figures 2, 5 and 6 for actuation of said plunger by said pin as will hereinafter appear.

The end of the locking lever 110 adjacent the pivot shaft 112 carries an insulating contact actuating member 144, and suitably mounted on the base casting 32 are two pair of normally open contacts and 146' which are actuable alternatively by the actuating memher 144. As shown most clearly in Figure 2, when the armature 118 of the latching means 114 is in atttracted position, the actuating member 144 holds the contacts 145 closed. Movement of the armature 118 to released position, however, pivots the locking arm 110 in acounterclockwise direction to move the contact actuating member 144 out of engagement with the contacts 145 and into engagement with the contacts 146 to move the latter to closed position while the contacts 145 move to open position.

Suitably mounted on the base casting 32 are a power transformer 147 and a knock out transformer 148. The power transformer 147 is provided with a primary winding 149 and a pair of reduced voltage secondary windings 150 and 151 as shown schematically in Figure 6; As also shown schematically in Figure 6, the knock out transformer 148 has a primary Winding 152 anda reduced voltage secondary winding 153'. The primary winding of the power transformer 147 is connected in circuit wtih a suitable source of electrical energy, forexample a source of alternating current 154 by means of conductors 155 and 156. The contacts 141 and142 are interposed in the conductor 155 in series circuit therewith, and a manually actuatable master switch 157 may be interposed in the conductor 156 as'shown.

One terminal of the motor 21 is connected by means of a conductor 158 in circuit with the portion of the conductor 155 extending between the contact 141 and the source 154. The other terminal of the motor 21 is connected in circuit with the conductor 156 by means of a conductor 159' which has the contacts 145 interposed therein; The aforementioned other terminal of the motor 21 is also connected in circuit with the conductor 156 by means of a conductor 16! in parallel with the conductor 159 and having a thermostatic fan switch 161 interposed therein. The switch 161 is preferably disposed within the casing 11 as shown, and the contacts thereof make when the temperature within the casing 11 is above a predetermined level and break when said temperature drops below a predetermined level.

The terminals of the driving motor 55 are connected in circuit with the secondary winding 151 of the transformer 147 by means of conductors 162 and 163. Interposed in the conductor 162 in series circuit relation are a thermostatic high limit switch 164 and a room thermostat 165. The high limit switch 164 is preferably disposed within the casing 11 and the contacts thereof are normally closed except when the temperature within said casing exceeds a predetermined safe high limit temperature. The room thermostat 165 functions in the usual manner, the contacts thereof moving into engagement in response to a drop in the room temperature below the control point for which said thermostat is set, and moving out of engagement in response to a rise in the room temperature above said control point. The energizing winding 117 of the electromagnet 115 of latching means 114 is connected in parallel circuit relation with the driving motor 55 by means of conductors 173 and 174. The secondary winding 150 of the power transformer 147 is connected in circuit with the igniter 31 by means of conductors 166 and 167, the latter having the contacts 97 interposed therein to control the energization of the igniter by current from the winding 150.

The primary winding 152 of the knock out transformer 148 is connected in circuit with the secondary winding 151 of the power transformer 147 by having one terminal thereof connected in circuit with the conductor 163 by a conductor 175, and having the other terminal thereof connected in circuit with the conductor 174 by means of a conductor 168, the latter having the contacts 146 interposed therein as shown. It will therefore be observed that the motor 55, winding 117 of latching means 114, and the primary winding 152 of the knock out transformer 148 are connected in parallel circuit relation. The energizing winding 81 of the latching means 77 is connected in circuit with the thermoelectric generator 30 by means of conductors 169 and 170. The secondary winding 153 of the knock out transformer 148 is interposed in the conductor 170, and the conductor 169 may have the contacts of a pressure sensitive switch 171 interposed therein as shown. Where the switch 171 is utilized, it is provided with a conduit 172 affording communication with the interior of the chamber member 15, so that said switch is sensitive to the pressures within said chamber member. The switch 171 may be responsive. to pressures somewhat below atmospheric to close the contacts thereof only after the blower 23 has lowered the pressure within the chamber member 15 to the controlling pressure. Since the contacts of the switch 171 are in the thermoelectric circuit, they are low resistance in character and preferably are enclosed to prevent contamination by foreign matter which would tend to increase the resistance thereof.

The operation of the unit heater under the control of the improved fuel flow and ignition control apparatus will now be described. With the parts of the improved control apparatus disposed as shown in Figures 1 to 6, gaseous fuel is delivered to the main burner 26 and pilot burner 28 and is burner thereat. The motor 21 is energized and operating so that the blower 23 draws fresh air into the fresh air inlet conduit 18 and exhausts the products of combustion from the combustion chamberheat exchanger unit 14 through the exhaust conduit 25. At the same time, the fan 22 draws fresh air through the throat 12 into the casing 11, through and around the unit 14 for heating thereby, and the heated air is discharged through the louvered opening 13'. The thermoelectric generator 30 senses the flame of the pilot burner 28 and produces sufficient thermoelectric energy to energize the winding 81 of the latching means 77 and hold the armature 82 in the attracted position shown. Simultaneously with energization of the motor 55 which is stalled by its movement of the main fuel valve to open position, the winding 117 of the latching means 114 is energized sufficiently to hold the armature 118 in the attracted position shown.

The unit heater 1!) normally continues operation in this manner until the room thermostat 165 no longer calls for heat and interrupts the circuit to the driving motor 55 and latching means 114, or the temperature within the casing 11 reachm an unsafe high limit temperature at which the high limit switch 164 interrupts the aforementioned motor and latching means circuit to afford complete shut off of all fuel fiow to the unit heater 10, as will hereinafter appear. More specifically, when such circuit interruption occurs, the. motor 55 is deenergized along with the winding 117 of the latching means 114, whereupon the armature 118 moves, under the bias of the spring 119 to its released position (not shown), thereby swinging the locking lever 110 in a counterclockwise direction toward the shaft 85. This movement of the lever 119 moves the upstanding locking lug 121 of said lever radially inwardly out of engagement with the coacting dependent locking log 94, to thereby release the lower bevel gear 91 for counterclockwise movement, thereby releasing the force transmitting connection afforded by the differential gear set between the driving motor 55 and the actuating roller 89'. As a result, the roller 89, together with the planet pinion 9t} and bevel gear 91, is moved in a counterclockwise direction under the bias of the tension spring 66 acting through the main valve arm 65, link '73 and its downturned lug 75, said spring bias, at the same time acting through the aforementioned arm 65, shaft 59 and main valve arm 63 to move the main fuel valve 64 toward closed position.

The aforementioned inward releasing movement of the locking lever 110 also relieves the tension of the tension spring 131 and permits the bias of the pilot valve spring 44 to simultaneously close the pilot valve 42 for extinguishment of the pilot burner 28 and, acting through the bell crank lever 43, arm 101 and shaft 106 to swing the arm 102 in a counterclockwise direction and thereby disengage the spur gear 105 from the splined portion of the shaft 85. This disengagement permits the torsion spring 107 to release the energy stored therein by rotating the gear in a clockwise direction until the pin 105 engages the edge of the arm 102. Simultaneously, the aforementioned counterclockwise movement of the arm 102, acting through the shaft 103 and the downturned lug 130, pulls the lever 123 outwardly therewith in a counterclockwise direction.

Still another direct result of the release movement of the lever is movement of the contact actuator 144 out of engagement with the contacts 145 and into engagement with the contacts 146 to effect opening of the contacts 145 and closure of the contacts 146. Opening of the contacts 145 at this point does not interrupt the operation of the blower motor 21, since the motor circuit is completed through the conductor and the fan switch 161, said motor continuing to operate until the temperature within the casing 11 has dropped to below the control point of the fan switch 161, at which time the contacts of said switch open and the motor 21 shuts off.

Closure of the contacts 146 has no effect until the motor and latching means circuit is again completed through the thermostat 165, and switch 164, at which time the closed contacts 146 effect energization of the knock out transformer 148 by alternating current from the secondary winding 151 to cause flow of the alternating current from the secondary winding 153 of the transformer 148 in the thermoelectric circuit of the latching means 77. If the aforementioned circuit completion takes place, for example by upward adjustment of the control point of the thermostat 165 while the generator 30 is still hot and energizing the latching means 77 and while the motor 21 is still operating to maintain the contacts of the switch 171 closed, the flow of alternating current in the thermoelectric circuit causes release of the armature 82 under the bias of the spring 83. As will hereinafter appear, this release of the armature 82 prevents opening of the main fuel valve while the pilot burner is extinguished and insures that said pilot burner is reignited before said main burner can be opened, thereby avoiding a hazardous condition.

On release of the armature 82 of the latching means 77, the shaft 76 pivots the lever 67 in a clockwise direction, and, acting through the link 71 also pivots the link 73 in a clockwise direction about the pin 74. This pivotal movement of link 73 swings the downturned lug 75 thereof radially outwardly of the path of the actuating roller 79 so that as long as the armature 82 is in released position, it is impossible for the actuating roller 89 to engage the downturned lug 75 for movement of the main fuel valve to open position.

The aforementioned completion of the circuit to the driving motor 55 and latching means 114 automatically initiates an ignition operation and upon successful ignition of the fuel at the pilot burner 28, the improved control apparatus automatically opens the main fuel valve to permit fuel flow to the main burner 26, which fuel is ignited by the flame of the pilot burner 28. More specifically, closure of the aforementioned circuit energizes both the driving motor 55 and the winding 117 of the latching means 114, energization and operation of said motor effecting clockwise rotation of the upper bevel gear 58 and rotation of the planet pinion about its axis. This gear and pinion rotation, in turn, causes counterclock wise rotation of the lower bevel gear 91 until one of the actuating lugs 93 engages the inner surface of the upper edge portion 121) (Figure of the locking lever 110. This engagement affords a resistance to further rotation of the lower gear 91, and as a result, continued rotation of the planet pinion 931 on its axis causes clockwise planetary movement of the latter and of the actuating roller 89, Which roller is thereby brought into engagement with the pivotal lever 67. The relative strength of the springs 33 and 119 of the latching means 77 and 114 respectively is such that once the actuating roller 39 engages the lever 67, the resistance to pivotal movement of the latter afforded by the spring 33 is greater than the resistance to pivotal movement of the locking lever 11h afforded by the spring 119, so that planetary movement of the roller 89 stops with engagement of the roller 39 with the lever 67, and continued rotation of the drive gear 58, by continued rotation of the planet pinion 911, on its axis, effects counterclockwise rotation of the lower bevel gear 91.

As a result, the actuating lug '33 in engagement with the locking lever 110 pivots the latter outwardly to thereby reset the armature 118 of the latching means 114 into attracted relation with the pole faces of the electromagnet 115. This resetting is effected before the resetting actuating lug 93 (Figure 5) moves beyond the upstanding locking lug 121 of the locking lever 111i, and as aforementioned the outward movement of the locking lever 1111 caused thereby exerts a pull on the connected end of the tension spring 131, which pull is transmitted through said spring to the lever 123. No inward movement of the. lever 123 takes place during the aforementioned resetting operation, however, because during said operation the actuating lug 93 opposite the re- 12 setting actuating lug 93 engages the inner surface of the upper edge portion 127 of the lever 123 to hold the latter outwardly in its initial position and prevent opening movement of the pilot valve 42 under the bias of spring 131. After the resetting actuating lug 93 moves beyond the upstanding lug 121 and out of engagement with the upper surface portion 126 of the locking lever so that said lever is free to move inwardly in the event that the armature 118 is not held in attracted position by the electromagnet 115, the opposite actuating lug 93 moves beyond the outturned lug 128 of the lever 123 to permit inward movement of said lever under the bias of the spring 131, and the locking lug 94 adjacent the resetting actuating lug 93 moves into engagement with the upstanding locking lug 121 of the lever 110 if the armature 11S remains attracted. Engagement of the locking lugs 94 and 121 locks the lower gear 91 against any substantial counterclockwise rotation, and the coaction of the opposite actuating lug 93 with the outturned lug 128 of the lever 123 locks the lower gear 91 against any substantial clockwise rotation.

The inward movement of the lever 123 under the bias of the spring 131 causes, by engagement of the downturned lug on said lever with the upper end of the shaft 103 carried by the arm 1112, clockwise swinging movement of said arm to move the spur gear 105 into meshing engagement with the splined portion 95 of the shaft 85 and at the same time to cause opening of the pilot valve 42, all against the bias of the spring 44. Fuel can now flow to the pilot burner 28. It will be observed that the pilot valve 42 cannot be opened in the improved apparatus until after resetting of the armature 118 of the latching means 114 has been completed and said armature is free to release and effect closure of the pilot valve in the event of power failure. With this arrangement, it is impossible for power failure to at any time result in the pilot valve 42 being held in open position to thereby create a hazardous condition.

Simultaneously with the outward pivotal movement of the lever 110, the contact actuator 144 moves out of engagement with the contacts 146 to permit opening of the latter for deenergization of the knock out transformer 148, and moves into engagement with the contacts to close the latter for completion of the power circuit between the source 154 and motor 21 through the conductors 155, 158, 159 and 156. Operation of the motor 21 causes the fan 22 to circulate fresh air through the housing 11, and the blower 23 to purge the combustion chamber-heat exchanger unit 14 by drawing fresh outside air in through the conduit 18 while discharging the gaseous contents of the unit 14 through the discharge conduit 25. In a system wherein the operation of the blower 23 is designed to produce a predetermined subatmospheric pressure within the unit 14 and the pressure sensitive switch 171 is utilized as aforementioned, and when the predetermined operating pressure within the unit 14- is sensed by the switch 171, the contacts of the latter are closed to complete the thermoelectric circuit. Until the contacts of switch 171 are closed in response to the pressure of the desired predetermined pressure in the unit 14 latching means 77 is inoperative and the main burner fuel valve 64 cannot be opened.

With the lower bevel gear 91 locked as aforedescribed, continued clockwise rotation of the drive gear 53 causes clockwise planetary movement of the planet pinion 9t) and of the actuating roller 89 which thereupon pushes the lever 67 outwardly, pivoting the latter in a counterclockwise direction to reset the armature $2 of the latching means 77 into engagement with the pole faces of the electromagnet 79. Simultaneously the cam 96, which rotates with the shaft 85 as the result of the aforementioned planetary movement of the pinion 91), engages the contacts 97 to close the ignitcr circuit and cause alternating current to flow from the secondary winding 154} of the transformer 147 through the conductors. 166. and 1 7 to the igniter element 31, causing the latter to heat up and ignite the fuel issuing from the pilot burner 28. The armature 82 is not normally held in attracted position when initially reset thereto because no substantial energizing current is supplied to said electromagnet by the thermoelectric generator 30 at this time, and as a result, said armature moves to retracted position and the lever 67 pivots in a clockwise direction as the actuating roller 89 moves out of engagement therewith. The planetary movement of the pinion 90 and actuating roller 89 continues, and without engaging the downturned lug 75 of the link 73, said roller again moves into engagement with the lever 67 to pivot the latter as before and reset the armature 82 to attracted position with respect to the pole faces of the electromagnet 79. During the aforementioned rotation cycle of the actuating roller 89, the flame of the pilot burner 28 had sutficient time to heat up the hot junction of the thermoelectric generator 30 sufficiently to cause the latter to generate a thermoelectric current of the magnitude to cause the electromagnet 79 to hold the armature 82 attracted thereto when again reset against the bias of the spring 83. This thermoelectric current, of course, flows through the winding 81 of the latching means 77 through the conductors 169 and 170, switch 171 and the secondary winding 153 of the knock out transformer 148.

Rotation of the shaft 85 as a result of the aforementioned planetary movement, causes counterclockwise rotation of the spur gear 105 and storage of energy in the torsion spring 107 (Figure In the event of failure of ignition of the fuel atthe pilot burner 28, the cycling planetary movement of pinion 90 and actuating roller 89 continues to reset the armature 82 to the pole faces of the electromagnet 79 of the latching means 77 without holding of said armature in attracted position until the resulting counterclockwise rotation of the spur gear 105 moves the upstanding pin 106 carried thereby into engagement with the conical tip 143 of the plunger 137 and pushes said plunger outwardly. This plunger movement disengages said plunger from the movable contact 142 (Figures 3 and 6) by positioning the reduced diameter portion 139 of said plunger below the contact 142 to permit the latter to move out of engagement with the contact 141 and open the circuit between the source 154 and the primary winding 149 of the power transformer 147.

The open circuit at contacts 141 and 142 deenergizes the power transformer 147 and hence the driving motor 55 and winding 117 of the latching means 114, stopping the motor 55 and effecting release of the armature 118 under the bias of the spring 119. The inward pivotal movement of the locking lever 110 resulting from release of armature 118 disengages the upstanding locking lug 121 of said lever from the coacting locking lug 94 of the lower gear 91 for release of said gear and at the same time relieves the tension of the spring 131 and permits the pilot valve spring 44 to swing the arm 102 in a direction to disengage the spur gear 105 from the splined portion 95 of the shaft 85 and pull the lever 123 therewith while closing the pilot valve 42 to shut off the flow of fuel to the pilot burner 28. Upon disengagement of the spur gear 105 from the splined portion 95 of the shaft 85, the energy stored in the torsion spring 107 effects return rotation of the spur gear 105 in a clockwise direction to its initial position wherein the depending pin 109 engages the edge of the arm 102 as hereinbefore described. All fuel flow is thus prevented and the apparatus remains completely shut down until the plunger 137 is again reset to close the power circuit at the contacts 141 and 142 and initiate another ignition cycle.

Ordinarily, the armature 82 of the latching means 77 is held in attracted position by the electromagnet 79 the second time it is reset thereto by planetary movement of the pinion 90 and actuating roller 89, and when so held, the lever 67, link 71 and link 73 are so disposed that the downturned lug 75 of link 73 is positioned in the path of the actuating roller 39. Thus, as the roller 89 moves out of engagement with the lever 67 after successfully resetting the armature 82., it continues planetary movement in a counterclockwise direction and moves into engagement with the downturned lug 75 to move the latter toward the right therewith as viewed in Figure 1. This movement of the link 73 causes clockwise pivotal movement of the valve arm 65 against the bias of main valve spring 66, and, through the shaft 59 and valve arm 63, causes opening movement of the main fuel valve 64 to permit fuel flow to the main burner 26, Clockwise movement of the valve arm 65 is limited by its engagement with the upstanding lug 49, and such engagement causes stalling of the drive motor 55 which remains stalled as long as it is energized to hold the main valve 64 in open position. Fuel emitted from the main burner 26 is ignited by the flame of the pilot burner 28, and the heat of this burning fuel is transferred through the walls of the unit 14 to the fresh air circulated through the casing 10 by the fan 22 and discharged into the space being heated.

As the temperature within the casing 11 rises, the contacts of the fan switch 161 engage to complete a parallel energizing circuit between the motor 21 and conductor 156 through the conductor 160, so that the motor 21 and fan 22 continue to operate after opening the contacts as long as the temperature within the casing 11 remains above a predetermined level. The parts of the improved apparatus are thus in the positions shown in Figures 1 to 6 of the drawing, and the unit heater 10 continues to operate until the room temperature sensed by the thermostat exceeds the control point level for which said thermostat is set, to cause opening of the contacts of said thermostat and complete shut down of the unit heater 10 as aforedescribed. The entire apparatus can also be completely shut down at any time by actuation of the master switch 157 to open position, thereby shutting off the flow of all alternating current power to the improved apparatus.

While the improved fuel control and ignition apparatus has been shown and described in connection with a unit heater 10 having a sealed type combustion chamber, it is equally adaptable for use in controlling the fuel flow to and ignition in fluid fuel burning equipment which operates at atmospheric pressure and does not require blower means for effecting circulating through the combustion chamber-heat exchanger unit thereof. In such a system, the blower 23 and pressure sensitive switch 171 are omitted along with conductor 159 and contacts 145. In the type of equipment wherein the blower 23 is omitted, the operation of the fan motor 21 is under the control of the thermostatic fan switch 161 and said motor does not operate until the temperature within the casing '11 reaches a predetermined level. Once operating, the motor 21 continues to operate, irrespective of the burning of fuel at the main and pilot burners, until the temperature within the casing 11 drops below the control point of the fan switch 161.

The improved fuel control and ignition apparatus is also equally adaptable for use in fuel burning equipment of the last-mentioned type type wherein it is desired to have the pilot burner 28 burning constantly. Where 'a constant burning pilot burner is used, the knock out transformer 148 is also omitted, along with the conductor 16% and contacts 146.

Figure 7 is a fragmentary plan view of the form of the improved fuel control and ignition apparatus which is adapted for use with equipment having a constant burning pilot burner. In Figure 7 the parts indicated by primed reference characters correspond to the parts in Figures 1 to 6 indicated by the same reference char acters unprimed. In Figure 7, the solid lines show the spur gear 105' in mesh with the splined portion 95' of the shaft 85, and its alternative position out of meshing engagement with said splined portion is shown in dot and dash lines. The corresponding positions of the arm 102' are shown in like manner. The solid line position of the lever 67, shaft 76 is the position of said parts when the armature 82 is held in attracted position with respect to the pole faces of the electromagnet 79. The position of the lever 67', shaft 76' corresponding to the released position of the armature 82, is shown in dot and dash lines. The arm 102' is formed with a projecting lug or shoulder portion 162a, and the lever 67 is provided with a detent member 67a, which may take the form of a generally U-shaped resilient member as shown.

In the operation of the form of the invention shown in Figure 7, the detent member 67a is movable with pivotal resetting movement of the lever 67 to the solid line position thereof shown in Figure 7 wherein it engages the shoulder portion 162a of arm 162'. The detent member 6% is operative to hold the arm 192 and the spur gear 195' in the solid line position thereof as long as the armature he remains in attracted position with respect to the pole faces of the electromagnet 79. This, of course, results in the pilot valve member being held in open position as long as the armature 82' is held in attracted position, and therefore as long as a flame is sensed at the pilot burner by the thermoelectric generator. In the event of pilot burner outage, however, the resulting deenergization of the electromagnet 79 permits release of the armature 82' and movement of the lever 67 to the dot and dash line position thereof shown in Figure 7, thereby disengaging the detent member 67a from the shoulder portion 102a of the arm 192' and permitting the pilot valve spring 44 to close the pilot valve and at the same time disengage the spur gear 105' from the splined portion 95' of the shaft 35.

In the apparatus of Figures 1 to 5 modified as shown in Figure 7, the armature 82 remains continuously in attracted position, and upon opening of the contacts at the thermostat 165, the driving motor 55 is deenergized and the armature 113 of the latching means 114 is released as aforedescribed to pivot the locking lever i ltl inwardly for disengagement of the upstanding locking lug 121 from the locking lug 94 and release of the lower gear 91 and of the force transmitting connection between the drive motor 55 and the actuating roller 89. On such release, the bias of the spring 66, acting through the arm 65 and link 73, moves the actuating roller 89 in a counterclockwise direction Without reversal of the drive gear 58, and at the same time effects, through the arm 65, shaft 59 and 63, closure of the main fuel valve 64 for shut off of the fuel flow to the main burner 26.

The counterclockwise planetary movement of the roller '89 and pinion 99 under the bias of the spring 66 is not sufiicient to move the cam 96 into actuating engagement with the ignition contacts 97, however. Therefore, when the circuit is again made at the thermostat 165 as the latter calls for heat, operation of the driving motor 55 again causes clockwise rotation of the drive gear 58 and clockwise planetary movement of the pinion 90 and acituating roller 89 to cause the latter to move toward and engage the downturned lug 75 of the link 73. The resistance offered by the spring 66 acting through the arm 65 and link 73, stalls the actuating roller 89 in its position of initial engagement with the lug 75, and continued rotation of the driving gear 53 thereupon causes counterclockwise rotation of the lower bevel gear '91 and movement of an actuating lug 93 into engagement with the locking lever lid. The last-mentioned lug 93 pivots the locking lever llltl outwardly to reset the armature 118 of the latching means 117 to attracted position in which it is held by the energized electromagnet 115.

As aforedescribed, when the resetting actuating lug 93 moves beyond the upstanding locking lug 121 of the lever 110, the adjacent locking lug 94 engages said upstanding looking lug to lock the lower gear 91 against further counterclockwise rotation While the opposite actuating lug 93 coacts with the outturned lug 136 to prevent clockwise rotation of said lower gear. With the lower gear 91 thus locked, continued rotation of the driving gear 58 causes clockwise planetary movement of planet pinion 90 and actuating roller 89 while the latter engages the downturned lug 75, overcoming the bias of the spring 66 and moving link 73 and arm 75 to the right therewith, to thereby open the main fuel valve 64 for the flow of fuel to the main burner 26. As aforedescribed, the energized motor 55 stalls when the arm 65 engages the upstanding lug 49 and said motor holds the main fuel valve open until the room thermostat 165 no longer calls for heat and interrupts the power circuit to said motor and latching means 114 by opening of the contacts of the room thermostat 165. The main fuel valve 64 can thus be cycled between open and closed positions in response to the requirements for heat sensed by the room thermostat 165, and such cycling takes place without effecting reversal of the drive gear 53 or motor shaft 56, and without elfecting reenergization of the igniter element 31.

In the event, however, of pilot burner outage, cooling of thermoelectric generator 30 effects release of the armature 82 of the latching means 77 under the bias of the spring 83 to pivot the lever 67 in a clockwise direction and, through the link 71, to pivot the link 73 about the pin 74 and move the downturned lug 75 outwardly out of engagement with the actuating roller 89 to permit closure of the main fuel valve under the bias of the spring 66. The energized motor 55 thereupon immediately initiates clockwise rotation of the drive gear 58, and since the lower gear 91 is still locked, thereby causes clockwise planetary movement of the pinion and actuating roller 89 into resetting engagement with the lever 67 to push the latter outwardly and reset the armature 82 into engagement with the pole faces of the electromagnet 79 while at the same time actuating the igniter contacts 97 to energize the igniter element 31. This normally ignites the fuel emitted from the pilot burner 28, as aforedescribed, for heating of the thermo electric generator 30. Since the generator 30 is cool at this point, the armature 82 is not held in attracted position, but on the next cycle of planetary rotation of the actuating roller 89, said armature is held in attracted position by virtue of energization of the electromagnet 79 by the thermoelectric energy produced in the heated generator 30.

Once the armature 82 remains attracted, the depending lug 75 of link 73 is again disposed in the path of the actuating roller 89, so that upon continued planetary rotation of said roller, the lug 75 is engaged thereby and moved therewith to effect opening of the main fuel valve for fuel flow to the main burner 26. In the event that the pilot burner fails to igniteafter a predetermined number of cycles of planetary movement of the actuating roller 89, the upstanding pin 11% of the spur gear is moved into engagement with the conical tip portion 143 of the plunger 137 and said plunger is thereby moved outwardly to interrupt the circuit at the contacts 14-1 and 142 and prevent further flow of alternating current to the power transformer 147 for shut down of the apparatus.

It is to be understood that numerous other changes and modifications of the invention are possible within the spirit of the invention. The illustrated forms of the invention have been selected for the purpose of disclosure only and are not intended to limit the forms which the invention may take or to confine the invention to a particular use, all of such other forms, modifications, or changes being contemplated as may come within the scope of the appended claims.

What is claimed as the invention is:

1. A fuel flow control device for fluid fuel burning apparatus having main and ignition burners comprising a main burner fuel valve having a closed position and movable toward an open position, first releasable holding means having a first electromagnet energizable in response to the presence of a flame at said ignition burner and a first armature movable between attracted and released positions with respect to said electromagnet and adapted to be held in attracted position by said electromagnet when the latter is energized and said armature is moved to said attracted position, a movable actuating member, an operative connection between said armature and said valve having a first portion engageable by said actuating member for moving said armature from released toward attracted position, said connection also including a second portion positioned for engagement by said actuating member when said armature is in attracted position and positioned out of the path of said actuating member when said armature member is in released position, a prime mover, a releasable force transmitting connection between said prime mover and said actuating member, second releasable holding means comprising a second electromagnet and a second armature movable between attracted and released positions with respect to said second electromagnet and aadpted to be held in attracted position by said second electromagnet when the latter is energized and said armature is moved to said attracted position, said second armature coacting with said force transmitting connection to release the latter when said second armature is released and to render said force transmitting connection operative to transmit actuating force from said prime mover to said actuating member when said second armature is in attracted position, said force transmitting connection including means powered by said prime mover for moving said second armature toward attracted position, said prime mover, acting through said force transmitting connection, being operable to move said second armature toward attracted position, and if said armature is held in attracted position, to cause said actuating member to engage said first portion of said operative connection and move said first armature toward attracted position, and if both of said armatures are held in attracted position to cause said actuating member to engage said second portion of said operative connection for move ment of said valve toward open position, whereby said main burner fuel valve can be moved toward open position by operation of said prime mover only when said second electromagnet is energized and a flame exists at said ignition burner.

2. A control device comprising a control member having a first position and movable toward a second position, first releasable latching means having a first latchable member movable between latched and released positions, a movable actuating member, an operative connection between said latchable member and said control member having a first portion engageable by said actuating member for moving said latchable member from released toward latched position, said connection also ineluding a second portion positioned for engagement by said actuating member when said latchable member is in latched position, said second portion being positioned out of the path of said actuating member when said latchable member is in released position, a prime mover, a releasable force transmitting connection between said prime mover and said actuating member, second latching means having a second latchable member movable between latched and released positions and coacting with said force transmitting connection to release the latter when said second latchable member is released and to render said force transmitting connection operative to transmit actuating force from said prime mover to said actuating member when said second latchable member is in latched position, said force transmitting connection including means powered by said prime mover for moving said second latchable member toward latched position, said prime mover, acting through said force transmitting connection,

being operable to move said second latchable member toward latched position, and if said member remains latched to cause said actuating member to engage said first portion of said operative connection and move said first latchable member toward latched. position, and if both latchable members remain latched to cause said actuating member to engage said second portion of said operative connection for movement of said control member toward its second position, whereby actuation of said control member by operation of said prime mover is dependent upon the operativeness of both of said latching means.

3. A fuel flow control device comprising a valve biased toward closed position and movable toward an open position, a prime mover, a releasable force transmitting connection between said prime mover and said valve comprising first and second coaxial and axially spaced gears and a planet pinion interposed between and meshing with said gears, a rotatable carrier for said planet pinion, means for driving said first gear by said prime mover, holding means comprising an electromagnet and a coacting armature having a releasable position and movable toward an attracted position in which it is held by said electromagnet when the latter is energized and said armature is in said attracted position, means on said second gear coacting with said armature to move the latter to said attracted position, means cooperable with said armature and second gear for looking the latter against rotation while said latchable member is latched to effect, by rotation of said first gear, planetary movement of said planet pinion, an actuating member on said planet pinion carrier movable with said planet pinion and operatively associated with said valve for moving the latter toward its open position in response to operation of said prime mover when said armature member is held in attracted position, deenergization of said electromagnet and release of said armature when said valve is being held open by said actuating member effecting release of said second gear to permit reverse movement of said actuating member and closure of said valve under said bias without reversal of said first gear and prime mover.

4. A control device comprising a control member biased toward a first position and movable toward a second position, a prime mover, a releasable force transmitting connection between said prime mover and said control member comprising first and second coaxial gears and a planet pinion meshing with said gears, said first gear being driven by said prime mover, latching means having a latchable member movable between latched and released positions, means on said second gear coacting with said latchable member to move the latter to said latched position, means locking said second gear against rotation while said latchable member is latched to effect, by rotation of said first gear, planetary movement of said planet pinion, an actuating member movable with said planet pinion and operatively associated with said control member for moving the latter toward its second position in response to operation of said prime mover when said latchable member is latched, release of said latchable member while said control member is being held in its second position by said actuating member eifecting release of said second gear to permit reverse movement of said actuating member and return of said control member to its first position without reversal of said first gear and prime mover.

5. A fuel flow control device for fiuid fuel burning apparatus having main and ignition burners comprising main and ignition burner fuel valves each having closed and open positions, first releasable holding means comprising an electromagnet energizable in response to the presence of a flame at said ignition burner, and an armature movable between attracted and released positions with respect to said electromagnet and adapted to be held in attracted position by said electromagnet when the 19 latter is energized and said armature is moved to said attracted position, electroresponsive actuating means including a cycling actuating member operatively associated with said armature for moving the latter from released toward attracted position, electroresponsive means operable when energized to coact with said actuating means to open said ignition fuel valve and hold the latter open, an operative connection between said armature and said main fuel valve having an abutment portion positioned for engagement by said cycling actuating member when said armature is in attracted position and positioned out of the path of said cycling actuating member when said armature is in released position, whereby said main burner fuel valve can be moved toward open position by operation of said actuating means only when a flame exists at said ignition burner, electroresponsive ignition means for said ignition burner energizable by operation of said cycling actuating member, and resettable shut-off means in circuit with said actuating means, said ignition means and said ignition fuel valve holding means for effecting release of said ignition fuel valve to permit closure thereof and for preventing further energization of said actuating means and said ignition means after a predetermined number of cycles of said actuating member following resetting of said shut-off means without ignition of the fuel at said ignition burner.

6. A control device comprising first and second control members each having a first position and movable toward a second position, releasable latching means having a latchable member movable between latched and released positions, electro-responsive actuating means including a cycling actuating member operatively associated with said latchable member for moving the latter from released toward latched position, means actuated by said actuating means for moving said second control member toward and holding the latter in its second controlling position, an operative connection between latchable member and said first control member including a movable abutment portion positioned for engagement by said cycling actuating member when said latchable member is in latched position, said portion being positioned out of the path of said actuating member when said latchable member is in released position, whereby said first control member can be moved toward its second position by said actuating member acting through said operative connection only when said latchable member is in latched position, and resettable shut-off means operatively associated with said holding means and said actuating means for releasing said second control member for movement toward its first position and for preventing further cycling of said cycling actuating member after a predetermined number of cycles of the latter following resetting of said shut-ofi means without said latching member being held in said latched position.

7. A fuel flow control device for fluid fuel burning apparatus having main and ignition burners comprising main and ignition burner fuel valves each having open and closed positions, actuating means for opening said main burner fuel valve, a prime mover, a releasable force transmitting connection between said prime mover and said actuating means, latching means comprising an electromagnet and a coacting armature movable between attracted and released positions and coacting with said force transmitting connection to release the latter when said armature is released and to render said connection operative to transmit actuating force from said prime mover to said actuating means when said armature is in attracted position, said connection including reset means powered by said prime mover for moving said armature toward attracted position, whereby said prime mover, acting through said force transmitting connection is operable sequentially to reset said armature toward attracted position and open said main burner fuel valve, an operative connection between said armature and said pilot burner fuel valve biasing the latter toward its second position when said armature is in attracted position, said reset means having a position effecting disposition of said armature in attracted position and also being movable to a second positionpermitting release movementofsaid armature, and means ,for preventing openingmovement of said pilot burner fuel valve under said bias except when said reset means is in itssaid second position, where- .by opening of both of said valves by operation of said prime mover is subject to energization of saidelcctromagnet, and closure of-said pilot burner fuel valve is independent of said prime mover.

8. A control device comprising first and second control members each having a first position and movable toward a second position, actuating means for moving said first control member from said first toward said second position, a prime mover, a releasable force tran mitting connection between said prime mover and said actuating means, latchingmeans having a latchable member movable between latched and released positions and coacting with said force transmitting connection to release the latter when said latchable member is released and to render said connection operative to transmit actuating force from said prime mover to said actuating'means when said latchable member is in latched position, said connection including reset means powered by said prime mover for moving said latchable member toward latched position, whereby said prime mover, acting through said force transmitting connection is operable sequentially to move said latchable member toward latched position and said first control member toward said second position, an operative connection between said latchable member and said second control member biasing the latter toward its second position when said latchable member is in latched position, said reset means having a position eifecting disposition of said latchable member in latched position and also being movable to a second position permitting release movement of said latchable member, and means for preventing movement of saidsecond control member toward its second position under said bias except when said reset means is in its said secondposition, whereby said second control member normally can be disposed in its second position under said bias only when said latching means is operative to hold said latchablemember in its latched position.

9. A control device for controlling the flow of fluid fuel to fuel burning apparatus having main and pilot burners, comprising main and pilot burner .fuel valves each having open and closed positions, an electroresponsive prime mover, an operative connection between said prime mover and said valves, said connection including means for effecting opening movement of said pilot fuel valve, resettable means for holding said pilot fuel valve in open position when moved thereto, said connection also including a rotatable actuating member cooperable with said holding means for resetting the latter to holding position with respect to said pilot fuel valve by initial movement of said actuating member through a resetting position, said actuating member also being cooperable with said main fuel valve by further movement when said pilot fuel valve is held in open position to efiect movement of said main fuel valve toward its open position, means stalling said energized prime mover when said main fuel valve is open, said operative connection afifording reverse movement of said actuating member from stalled position toward a retracted position short of said resetting position on deenergization of said prime mover to permit closingmovement of said main fuel valve, an igniter switch operatively associated with said actuating member for actuation to an energizing position prior to disposition of said actuating member in said retractcdposition, whereby after initial actuation of said igniter switch by said actuating member said main fuel valve can be cycled between its closed and open positions by energization and 21 deenergiza'tion of said prime mover without corresponding cycling of said igniter switch.

10. In a control device having first and second control members each having a first position and movable toward a second position, an electroresponsive prime mover, an operative connection between said prime mover and said control members, said connection including means for moving said first control member toward its second position, resettable means for holding said first control member in its second position when moved thereto, said connection also including a rotatable actuating member cooperable with said holding means for resetting the latter to holding position with respect to said first control member by initial movement of said actuating member through a resetting position, said actuating member also being cooperable with said second control member by further movement when said first control member is held in its first position to move said second control member toward its second position, means stalling said energized prime mover when said second control member is in its second position, said operative connection affording reverse movement of said actuating member from stalled position toward a retracted position on deenergization of said prime mover to permit movement of said second control member toward its first position, an igniter switch operatively associated with said actuating member for actuation to an energizing position prior to disposition of said actuating member in said retracted position, whereby after initial actuation of said igniter switch by said actuating member said second control member can be cycled between its first and second positions by energization and deenergization of said prime mover without corresponding cycling of said ignter switch.

11. In a control device for controlling the flow of fluid fuel to fuel burning apparatus having main and pilot burners, comprising main and pilot burner fuel valves each having open and closed positions, an electroresponsive prime mover, an operative connection between said prime mover and said valves, said connection including means for moving said pilot fuel valve toward its open position, releasable holding means comprising an electromagnet and an armature movable between attracted and released positions with respect to said electromagnet, energizing means for said electromagnet sensitive to the presence or absence of a flame at said pilot burner, a rotatable actuating member operatively associated with said armature for resetting the latter toward attracted position by initial operation of said prime mover effecting movement of said actuating member through a resetting position, said connection including an abutment portion positioned for engagement by said actuating member when said armature is in latched position to move, by further operation of said prime mover, said main fuel valve toward its open position, said abutment portion being positioned out of the path of said actuating member to prevent such actuation of said main fuel valve when said armature is in released position, means operatively associated with said armature for retaining said pilot fuel valve in its open position as long as said armature remains attracted, means stalling said energized prime mover when said main fuel valve is in its open position, said operative connection affording reverse movement of said actuating member from stalled position toward a retracted position on deenergization of said prime mover to permit movement of said main fuel valve toward its closed position, said connection also affording disengagement of said abutment portion from said actuating member for movement of said main fuel valve toward its closed position on release of said armature member, whereby said main fuel valve is cycled between its closed and open positions by energization and deenergization of said prime mover without reversal of the latter and said pilot fuel valve is held in its open position as long as said armature is held in attracted position by energization of said electromagnet in response to the presence of a flame at said pilot burner, outage of said pilot burner flame effecting release of said armature to permit disposition of both of said valves in their closed positions.

12. In a control device having first and second control members each having first and second positions, an electroresponsive prime mover, an operative connection between said prime mover and said control members, said connection including means for moving said first control member toward its second position, releasable latching having a latchable member movable between latched and released positions, a rotatable actuating member operatively associated with said latchable member for resetting the latter toward latched position by initial operation of said prime mover effecting movement of said actuating member through a resetting position, said connection including an abutment portion positioned for engagement by said actuating member when said latchable member is in latched position to move, by further operation of said prime mover, said second control member toward its second position, said abutment portion being positioned out of the path of said actuating member to prevent such actuation of said second control member when said latchable member is in released position, means operatively associated with said latchable member for retaining said first control member in its second position as long as said latchable member remains latched, means stalling said energized prime mover when said second control member is in its second position, said operative connection affording reverse movement of said actuating member from stalled position toward a retracted position on deenergization of said prime mover to permit movement of said second control member toward its first position, said connection also affording disengagement of said abutment portion from said actuating member for movement of said second control member toward its first position on release of said latchable member, whereby said second control member is cycled between its first and second positions by energization and deenergization of said prime mover without reversal of the latter and said second control member is held in its second position as long as said latchable member is held in latched position, release of said latchable member permitting disposition of both of said control members in their first positions.

13. A fuel flow control device for fluid fuel burning apparatus having main and ignition burners comprising a main burner fuel valve biased toward a closed position and movable against said bias toward an open position, releasable holding means comprising an electromagnet energizable in response to the presence of a flame at said ignition burner, and an armature biased toward a released position and movable against said bias toward an attracted position with respect to said electromagnet, said armature being held in attracted position by said electromagnet when the latter is energized and said armature is moved to said attracted position against its bias, a movable actuating member mounted for rotation, and an operative connection between said armature and said valve having a first portion engageable by said actuating member when the latter is moved in one direction of rotation for moving said armature from released toward attracted position against its bias, said connection also including a second portion positioned for engagement by said actuating member for actuation thereby to open said valve by continued movement of said actuating member in said one direction when said armature is in attracted position, said second portion being positioned out of the path of said actuating member when said armature is in released position, release of said armature on deenergization of said electromagnet when the valve is positioned in open position by said actuating member causing disengagement of said actuating member from said second portion and thereby from said operative connection to permit return of said Valve toward closed position under its bias, whereby said main burner fuel valve can be moved toward open position by said actuating member moving in saidone direction and acting through said operative connection only when a flame exists at said ignition burner, and said valve when open is moved toward closed position in response to pilot burner outage.

14. A fuel flow control device for fluid fuel burning apparatus having main and ignition burners comprising a mainburner fuel valve having a closed position and movable toward an open position, releasable holding means comprising an electromagnet energizable in response to the presence of a flame at said ignition burner, and an armature movable between attracted and released positions with respect to said electromagnet and adapted to be held in attracted position by said electromagnet when the latter is energized and said armature is moved to said attracted position, a movable actuating member mounted for rotation, and an operative connection between said armature and said valve having a first portion engageable by said actuating member when the latter is moved in one direction of rotation for moving said armature from released toward attracted position, said connection also including a second portion positioned for engagement by said actuating member upon continued movement of the latter in said one direction when said armature is in attracted position and positioned out of the path of said actuating member when said armature is in released position, whereby said main burner fuel valve can be moved toward open position by said actuating member moving in said one direction and acting through said operative connection only when a flame exists at said ignition burner.

15 A control device comprising a control member biased toward a first position and movable toward a secend position, releasable latching means having a latchable member movable between latched and released positions, a movable actuating member mounted for rotation, and an operative connection between said latchable member and said control member having a first portion engageable by said actuating member when the latter is moved in one direction of rotation tor moving said latchable member flom released toward latched position, said connection also including a second portion positioned (for engagement by said actuating member upon continued movement of the latter in said one direction when said latchable member is in latched position and positioned out of the path oat said actuating member when said latchablemember is in released position, whereby said control member can be moved toward its second position by said actuating member moving in said one direction and acting through said operative connection only when said latchable member is in latched position, release of said latching means when the control member is positioned in its second position by said actuating member causing disengagement of said actuating member from said second portion and thereby from said operative connection to permit return movement of said control member toward its first position.

16. A control device comprising a control member having a first position and movable toward a second position, releasable latching means having a latchable member movable between latched and released positions, a movable actuating member mounted for rotation, and an operative connection between said latchable member and said control member having a first portion engageable by said actuating member when the latter is moved in one direction of rotation ior moving said latchable member [from released toward latched position, said connection also including a second portion positioned for engagement by said actuating member upon continued movement of the latter in the same direction when said latchable member is in latched position and positioned out of the path of said actuating member when said latchable member is released position, whereby said control 24 member can be moved toward its second position by said actuating member moving in said one direction and acting through said operative connection only when said latchablelmember is in latched position.

17. A control device comprising a control member having a first position and movable toward a second position, releasable latching means having a latchable member movable between latched and released positions, a movable actuating member mounted for rotation and operatively associated with said latchable member for moving the latter from released toward latched position by movement of said actuating member in one direction oi rotation, and an operative connection between said latchable member and said control member including a portion positioned for engagement by said actuating member upon continued movement of the latter in the same direction when said latchable member is in latched position and positioned out of the path of said actuating member when said latchable member is in released position, whereby said control member can be moved toward its second position by said actuating member moving in said one direction and acting through said operative connection only when said latchable member is in latched position.

18. A fluid fuel control device comprising a valve having closed and open positions, an actuating member for effecting opening movement of said valve, a prime mover, a releasable force transmitting connection between said prime mover and said actuating member, an electromagnet [and a coacting armature having a released position and movable to an attracted position in which it is held by said electromagnet when the latter is energized and said armature is moved to said attracted position, said armature coacting with said .force transmitting connection to release the latter when said armature is released :and to render said connection operative to transmit actuating force from said prime mover directly to said actuating member to cause movement of the latter in one direction to an operative position for actuation of said valve toward open position when said armature is in attracted position, release of said force transmitting connection permitting reverse movement of said actuating member to an inoperative position for return of said valve toward closed position without reversal of said prime mover, said connection including means powered by said prime mover for resetting said armature member to attracted position, whereby operation of said prime mover generates force which is transmitted initially to said resetting means to reset said armature and render said force transmitting connection operative to thereafter transmit the force generated by continued operation of said prime mover directly to said actuating member to move the latter firom said inoperative toward said operative position for opening movement of said valve.

19. A control device comprising a control member having a first position and movable toward a second position, an actuating member for moving said control member from said first toward said second position, a prime mover, a releasable force transmitting connection between said prime mover and said actuating member, latching means having a latchable member movable between latched and released positions and coacting with said force transmitting connection to release the latter when said latchable member is released and to render said connection operative to transmit actuating force from said prime mover directly to said actuating member to cause movement of the latter in one direction to an operative position for actuation of said control member toward its second position when said latchable member is in latched position, release of said force transmitting connection permitting reverse movement of said actuating member to an inoperative position for return of said control member toward its first position without reversal of said prime mover, said connection including means powered by said prime mover for resetting .said latchable membertoward latched position, whereby operation of said prime mover generates force which is transmitted initially to said resetting means to reset said latchable member and render said force transmitting connection operative to there after transmit the force generated by continued operation of said prime mover directly to said actuating member to move the latter from said inoperative toward said operative position for movement of said control member from said first toward said second position.

20. A fluid fuel flow control device comprising a valve having closed and open positions, an actuating member for moving said valve from said closed toward said open position, a prime mover, a releasable force transmitting connection between said prime mover and said actuating member, electromagnetic holding means comprising an electromagnet and a coacting armature biased toward a released position and having an attracted position in which it is held by said electromagnet when the latter is energized and said armature is moved to said position against its bias, said armature coacting with said force transmitting connection to release the latter when said armature is released and to render said connection operative to transmit actuating force from said prime mover directly to said actuating member when said armature is held in attracted position, said connection including resetting means powered by said prime mover for moving said armature toward attracted position, whereby when said e-lectromagnet is energized, operation of said prime mover generates force which is transmitted to said resetting means to reset said armature and render said force transmitting connection operative to thereafter transmit the force generated by continued operation of said prime mover directly to said actuating member for movement thereby of said valve toward open position.

21. A control device comprising a control member having a first position and movable toward a second position, an actuating member for moving said control member from said first toward said second position, a prime mover, a releasable force transmitting connection between said prime mover and said actuating member, latching means having a latchable member movable between latched and released positions and coacting with said force transmitting connection to release the latter when said latchable member is released and to render said connection operative to transmit actuating force from said prime mover directly to said actuating member when said latchable member is in latched position, said connection including resetting means powered by said prime mover for moving said latchable member toward latched position, whereby operation of said prime mover generates force which is transmitted initially to said resetting means to reset said latchable member and render said force transmitting connection operative to thereafter transmit the force generated by continued operation of said prime mover directly to said actuating member for movement thereby of said control member toward its second position.

22. In a fuel flow control device for controlling fuel flow to a burner having a valve movable to open and closed positions and having a prime mover, an operative connection between said prime mover and valve comprising holding means including an electromagnet and a coacting armature having an attracted position in which it is held by said electromagnet when the latter is energized and said armature is moved to said position, said armature also having a released position, actuating means driven by said prime mover and including an actuating member operatively associated with said armature and movable to a first position effecting disposition of said armature in attracted position, said actuating member also being movable to a second position permitting release movement of said armature, an operative connection between said armature and said valve including spring means having a normal substantially undeformed condition in which it is disposed when said armature is in released posi- .26 tion, said spring means being positioned. for deformation by'movement of said armature to attracted position and when thus deformed being operable to bias said valve to ward open position independent of said actuating member, means for preventing opening movement of said valve under said bias except when said actuating member is in its said second position, and flame sensitive means for retaining said valve in open position when moved thereto as long as a flame exists at said burner, wherebyopening of said valve by operation of said prime mover is subject to energization of said electromagnet and closure of said valve on flame outage is independent of said prime mover.

23. A control device comprising a control member having a first position and movable toward a second position, latching means including a latchable member having a latched position and movable toward a released position, an actuating member operatively associated with said latchable member and movable to a first position effecting disposition of said latchable member in latched position, said actuating member also being movable to a second position permitting release movement of said latchable member, an operative connection between said latchable member and said control member including spring means having a normal substantially undeformed condition in which it is disposed when said latchable member is in released position, said spring means being positioned for deformation by movement of said latchable member to latched position and when thus deformed being operable to bias said control member toward its second position independent of said actuating member, means for preventing movement of said control member toward its second position under said bias except when said actuating member is in its said second position, and condition responsive means for retaining said control member in its second position when moved thereto as long as a predetermined condition obtains.

24. In a fuel flow control device having a valve movable to open and closed positions and having a prime mover, an operative connection between said prime mover and valve comprising holding means including an electromagnet and a coacting armature having an attracted position in which it is held by said electromagnet when the latter is energized and said armature is moved to said position, said armature also having a released position, actuating means driven by said prime mover and including an actuating member operatively associated with said armature and movable to a first position eflecting disposition of said armature in attracted position, said actuating member also being movable to a second position permitting release movement of said armature, an operative connection between said armature and said valve including spring means having a normal substantially undeformed condition in which it is disposed when said armature is in released position, said spring means being positioned for deformation by movement of said armature to attracted position and when thus deformed being operable to bias said valve toward open position independent of said actuating member, and means for preventing opening movement of said valve member under said bias except when said actuating member is in its said second position, whereby opening of said valve by operation of said prime mover is subject to energization of said electromagnet, and closure of said valve is independent of said prime mover.

25. A control device comprising a control member having a first position and movable toward a second position, latching means including a latchable member having a latched position and movable toward a released position, an actuating member operatively associated with said latchable member and movable to a first position effecting disposition of said latchable member in latched position, said actuating member also being movable to a second position permitting release movement of said latchable member, an operative connection between said latchablevmember and said control member including spring References'Cited in the file of this patent UNITED STATES PATENTS Gille Nov. 21, 1939 Sparrow June 17, 1941 Di Vette Nov. 9, 1943 Kronmiller July 5, 1949 Riehl June 16, 1953 Aubert Nov. 3, 1953 Johnson et a1. Mar. 8, 1955 Thornbery Apr. 5, 1955 

